Earth/Ground Tester
Advanced Operation
25
From the indicated resistance value R
E
, the soil resistivity calculates according to the
equation:
EE
Ra..2
=
ρ
E
...... mean value of soil resistivity (Ωm)
R
E
...... measured resistance (Ω)
a ...... probe distance (m)
The measuring method according to Wenner determines the soil resistivity down to a
depth of approx. the distance "a" between two earth stakes. By increasing "a", deeper
strata can be measured and checked for homogeneity. By changing "a" several times, a
profile can be measured from which a suitable earth electrode can be determined.
According to the depth to be measured, "a" is selected between 2 m and 30 m. This
procedure results in curves depicted in the graph below.
Distances of Probe
Soil restivity ρE
A
2
1
3
edw021.eps
Curve 1: As ρE decreases only deeper down, a deep earth electrode is advisable
Curve 2: As ρE decreases only down to point A, an increase in the depth deeper
than A does not improve the values.
To Next Page
Loading...
Need help?
General
Weight and Dimensions
